Philosophy of Aquinas
Our society considers the work of Thomas Aquinas as early philosophy. However, his arguments and themes in one of his best known body of works, Summa Theologiae, draw heavily from that of former philosophical giants—ones such as Aristotle or Augustine. On that note, one of Augustine major accomplishments included defining mind-body dualism and materialism—an important distinction in philosophy. According to Augustine, Materialists believe that the mind exists as a part somewhere in the body; whereas dualists believe they are two wholly separate entities.
In his Summa Theologiae, Aquinas pays homage to this philosophy by devoting an entire section to this concept. However, in this section entitled Treatise on Human Nature, Aquinas does not provide clearly whether or not he conforms to the Dualist or Materialist ideals defined by the philosophers before him. It can be inferred though, that Aquinas does in fact conform to a dualist perspective in his discussion of the essence of soul and the union of the and body, for he, as the title reveals, makes a clear distinction between the two.
Aquinas first indicates his position regarding mind body dualism in his argument entitled “Is a soul a body? ” Aquinas inconveniently defines what he means by a “soul” in the next passage, by stating it is “principle of intellectual operations”. Through this definition it becomes clear that the soul is an entity capable of almost all cognitive processes, concordant with Augustine’s definition of the mind. Because the two definitions correlate, the two terms—in regards to Aquinas—can be used interchangeably.
Aquinas then states that “it is most surely and generally clear that the soul is not a body. ” Since the soul is a principle, it cannot be a body. “Otherwise an eye would be a soul, given that it has the principle of seeing. ” Either “each body would [exist] or would be a principle of life. ” The two cannot be the same. This correlates exactly to the inherent nature of dualism. The mind and the body exist separately—dually—as two entirely different entities.
Thus from the start, Aquinas makes it clear that he does in fact conform to a dualistic perspective on the subject of the mind’s relationship with the body. Aquinas continues to support dualism in his next passage, “Is a human soul something subsistent? ” In this, he argues that the soul seems to be subsistent. Since the soul can go through various intellectual capacities, “it has an operation on its own in which the body does not share. ” The process of thinking and other cognitive processes are unique to the mind and cannot be undertaken by the body.
He thus makes another distinction between the mind’s facilities and how they differentiate from the body’s. However, a materialist might draw the argument that subsistency indicates that the soul exists as a body, as something of material substance. Aquinas does in fact make a distinction between subsistency and being a body. He states that a soul exists as “an incorporeal and subsistent principle,” explicitly specifying that his definition of subsistency differs from that of corporeality, or having a body.
Aquinas merely uses the concept of subsistency to demonstrate how the mind truly exists, even though it does not exist physically as a body. Aquinas pays homage to Aristotle’s concept of hylomorphism in his passage entitled “Is a [human soul] composed of matter and form. ” This principle proposes that all “ordinary substances are composites of matter and form” This subscribes readily to the dualist perspective when applied to the relationship between mind and body.
Firstly, the “nature of the soul” as “the form of a body” intrinsically leads us to the conclusion that it exists as simply the form with the body as matter. Secondly, “The specific nature of a human soul…is intellective,” Aquinas states, because that is how Aquinas defines the soul. This “intellective soul has cognition of an entity in that entity’s nature taken absolutely,” thus, because it has “the form of a [human] taken absolutely…according to proper formal notion.
It can be concluded that “the intellective soul is an absolute form and not something composed of matter and form. ” In proving that the mind embodies the form of humans exclusively, Aquinas implies that the human body is simply the matter and thus a human is composed of a soul and a body—undeniably dualism. Aquinas’s passage “Does the soul exist as a whole part of the body? ” would be highlighted by materialists or those arguing against the fact that Aquinas places faith in dualism. In it Aquinas expressly states that “the soul exists as a whole in each part of the body”.
Taken at face value, this appears to refute the idea that Aquinas believes in dualism, for an implication might be that the soul physically within the body. However, Aquinas clarifies this statement by stating, that “the soul is in fact united to the body in form, it must exist in the whole body and [therefore] in each part of the body. ” Indicating that the soul exists within the body doesn’t actually refer to the physical presence of the soul. As mentioned earlier by Aquinas, the soul is incorporeal and is not a body.
Aquinas states simply that “the soul is in fact united to the body as its form; it must exist in the whole body and in each part of the body. ” He means that in order for the soul to be the form of the body, it must also be innately—not physically—in every part of the body. A bronze statue is composed of bronze and is a statue. Each piece of bronze on the statue is part of the whole. The foot, separated from the statue, still retains the original aspect of the statue. It is merely a part of the whole meaning it contains the bronze and was from a statue.
By stating the soul is within every part of the body, Aquinas merely refers to the inseparable quality of a substance’s form and matter. He does not refute his earlier statement that a soul is not a body, nor does he refute that the two are completely different—for this entire passage remains true to hylomorphism. Thus he remains a dualist. Aquinas’s earlier discussion regarding the human soul’s corruptibility could have been brushed off as irrelevant, but in retrospect it defines the most important distinction between the mind and body.
Aquinas believes that the human soul cannot have an end or be corrupted. This is because, Aquinas argues, it is wholly impossible for a form to cease to exist and something with intellectual properties would have a natural desire to not reach and end—since natural desire cannot be in vain, the human soul cannot be corrupted. The former makes sense intrinsically, even after the bronze statue has rusted to shreds, it can be re-created because its form is still known from the original. The bronze cannot be saved, it has reached an end, but its form can still be ascertained.
The principle of “natural desire” is not so obviously understood, yet is irrelevant to the concept of dualism. A dualist would remark that the mind and body differ completely. This ability to expire or continue existence indefinitely is an immense difference. Since Aquinas stands by his theory of a human soul’s incorruptibility, he is without question indicating a dualist perspective in that he maintains this vast difference between one’s infinitely existing mind and one’s mortal body.
In a discussion involving materialists and dualists, it is quite certain that Aquinas would argue for the dualists. He has made no indication in Summa Theologiae that the soul exists physically in the body or as a material body. He subscribes to hylomorphism, the theory that all substances are made of both matter and form. This concept basically defines the dualist perspective. The soul is simply the principle or the form of a human.